Multilayer printed board
A multilayer printed board has at least a signal layer, a power source layer, and a ground layer that are formed one upon another with insulation material being interposed among the layers. The board is capable of reducing radio waves to be emitted from the board.The board is provided with capacitors that are continuously or discretely formed at the edges of an overlapping pattern of the power source layer and ground layer, to pass a high-frequency current from the power source layer to the ground layer, thereby reducing the emission of radio waves.
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Claims
1. A multilayer printed board, comprising:
- a signal layer, a power source layer, and a ground layer formed one upon another with first insulation material, having a first relative permittivity, interposed therebetween;
- capacitor means, formed continuously or discretely along a periphery of an overlapping pattern of the power source layer and the ground layer for passing a high-frequency current from the power source layer to the ground layer and comprising a second insulation material having a second relative permittivity, larger than the first relative permittivity arranged between the power source layer and the ground layer along the periphery of the overlapping pattern.
2. The multilayer printed board of claim 1, wherein each capacitor comprises capacitor parts.
3. The multilayer printed board of claim 2, wherein each of the capacitor parts is connected in series with a respective resistor.
4. The multilayer printed board of claim 1, wherein the capacitor means comprises discrete capacitors, arranged at respective corners of the periphery of the overlapping pattern.
5. The multilayer printed board of claim 1, wherein the capacitor means comprises discrete capacitors arranged at respective corners of the overlapping pattern.
6. A multilayer printed board, comprising:
- a signal layer, a power source layer, and a ground layer formed one upon another with first insulation material, having a first relative permittivity, interposed therebetween;
- capacitor means, formed continuously or discretely along a periphery of an overlapping pattern of the power source layer and the ground layer for passing a high-frequency current from the power source layer to the ground layer and comprising:
- first electrodes protruding from the power source layer toward the ground layer along the periphery of the overlapping pattern; and
- second electrodes protruding from the ground layer toward the power source layer along the periphery of the overlapping pattern, each pair of adjacent first and second electrodes defining a corresponding capacitor.
7. A multilayer printed board, comprising:
- a signal layer, a power source layer, and a ground layer formed one upon another with first insulation material, having a first relative permittivity, interposed therebetween:
- capacitor means, formed continuously or discretely along a periphery of an overlapping pattern of the power source layer and the ground layer, for passing a high-frequency current from the power source layer to the ground layer; and
- additional capacitor means, formed along the periphery of the overlapping pattern and connected in parallel with the first capacitor means, for passing a high-frequency current from the power source layer to the ground layer, the power source layer being electrically connected to the signal layer at the periphery of the overlapping pattern to form the additional capacitor means.
8. A multilayer printed board, comprising:
- a signal layers a power source layer, and a ground layer formed one upon another with first insulation material, having a first relative permittivity, interposed therebetween,
- capacitor means, formed continuously or discretely along a periphery of an overlapping pattern of the power source layer and the ground layer for passing a high-frequency current from the power source layer to the ground layer; and
- additional capacitor means, formed alone the periphery of the overlapping pattern and connected in parallel with the first capacitor means, for passing a high-frequency current from the power source layer to the ground layer, the ground layer being electrically connected to the signal layer at the periphery of the overlapping pattern, to form the additional capacitor means.
9. A multilayer printed board, comprising:
- a signal layer, a power source layer, and a ground layer formed one upon another with first insulation material, having a first relative permittivity, interposed therebetween;
- capacitor means, formed continuously or discretely along a periphery of an overlapping pattern of the power source layer and the ground layer for passing a high-frequency current from the power source layer to the ground layer; and
- additional capacitor means, formed along the periphery of the overlapping pattern and connected in parallel with the first capacitor means, for passing a high-frequency current from the power source layer to the ground layer, and comprising additional insulation material formed on an end of the printed board along the periphery of the overlapping pattern and covered with conductive material, one of the ground layer and the power source layer being electrically connected to the conductive material and the other thereof being connected to the additional insulation material.
10. A multilayer printed board, comprising:
- a signal layer, a power source layer, and a ground layer formed one upon another with a first insulation material, having a first relative permittivity, interposed therebetween, the power source layer and the ground layer having an overlapping pattern defined by a periphery; and
- a second insulation material having a second relative permittivity, larger than the first relative permittivity, arranged between the power source layer and the ground layer along the periphery of the overlapping pattern thereof and forming a continuous capacitor extending along, or plural discrete capacitors at spaced positions along, the periphery of the overlapping pattern and passing high-frequency current from the power source layer to the ground layer.
11. The multilayer printed board as recited in claim 10, wherein:
- the second insulation material forms discrete capacitors positioned at respective corner portions of the periphery of the overlapping pattern.
12. The multilayer printed board as recited in claim 10, further comprising an additional continuous capacitor, or additional discrete capacitors, formed at the edges of the printed board along the periphery of the overlapping pattern and connected in parallel with the continuous capacitor or plural discrete capacitors, respectively, between the power source layer and the ground layer and passing a high-frequency current from the power source layer to the ground layer.
13. The multilayer printed board as recited in claim 12, wherein the power source layer is electrically connected to the signal layer at the periphery of the overlapping pattern, to form the additional continuous capacitor or additional discrete capacitors.
14. The multilayer printed board as recited in claim 12, wherein the ground layer is electrically connected to the signal layer at the periphery of the overlapping pattern, to form the additional continuous capacitors or discrete capacitors.
15. The multilayer printed board of claim 12, further comprising additional insulation material formed on the end of the printed board along the periphery of the overlapping pattern and covered with conductive material, one of the ground layer and the power source layer being electrically connected to the conductive material and the other thereof being connected to the additional insulation material, to form the additional continuous capacitor or additional discrete capacitors.
16. The multilayer printed board of claim 15, wherein the discrete capacitors are arranged at respective corners of the overlapping pattern.
| 5081561 | January 14, 1992 | Smith |
| 5376759 | December 27, 1994 | Marx et al. |
| 5523921 | June 4, 1996 | Van Lydegraf |
| 5708400 | January 13, 1998 | Morris |
| 5781110 | July 14, 1998 | Habeger, Jr. et al. |
| 5793098 | August 11, 1998 | Uchida |
| 53-068870 | June 1978 | JPX |
| 1-164057 | June 1989 | JPX |
Type: Grant
Filed: Nov 17, 1997
Date of Patent: Jul 20, 1999
Assignee: Fujitsu Limited (Kawasaki)
Inventors: Tomoyuki Nakao (Kawasaki), Shinya Yamaguchi (Kawasaki), Makoto Mukai (Kawasaki), Shinichi Ohtsu (Kawasaki)
Primary Examiner: Leo P. Picard
Assistant Examiner: John B. Vigushin
Law Firm: Staas & Halsey
Application Number: 8/971,901
International Classification: H05K 116; H05K 103;
